Good explanation, I wasn't aware that was how it worked. Time to
switch all my edit pages to use detachable models!
One more question on this topic (changing the subject of the thread)
Consider the scenario:
* Your edit page uses a detachable model to hold your business object.
* The user edits an object succesfully.
* On a later page, the user deletes the object.
* Then uses the back button to navigate back to the edit page, and
hits reload, or tries saving the object again.
The detachable model will fire, and will fail to load the object from
the DB. Depending on how your DAO is implemented, this will either
return null or throw an exception. Do you have a recommendation on
how to handle this scenario? Would you just check for null/catch the
exception and do a redirect to an error message page?
Thanks!
On Jan 31, 2008, at 7:23 PM, Nick Heudecker wrote:
Answer inline.
On Jan 31, 2008 8:42 PM, Sam Barnum <[EMAIL PROTECTED]> wrote:
Question on detachable models:
You use detachable models in the contact edit page. It seems like
this would cause your changes to be lost if the edit process takes
more than one request to complete.
If you use the no-arg constructor, the loadableDetachableModel
creates a new contact at the beginning of every request. If you
enter a name that's too long, a validation message is displayed. Then
the detach() is called on the model, and a new Contact is loaded on
the next request, erasing your temporary changes.
If validation fails, the input isn't copied to the Contact object.
The form
input is only copied to the Contact object when the form successfully
submits.
I may well be misunderstanding something, I'm fairly new to this
stuff. It seems that for edit pages you want a non-detachable model,
which gets serialized to the session.
I had the same misconception when I started using Wicket.
Thanks for taking the time to write this article, and thanks in
advance for any clarification on this topic.
--
Sam Barnum
360 Works
http://www.360works.com
415.865.0952
On Jan 28, 2008, at 11:02 AM, Nick Heudecker wrote:
It's finally up:
http://www.theserverside.com/news/thread.tss?thread_id=48234
Thanks to the various reviewers that helped improve both the
content and
quality of the article, including Martijn, Eelco, Igor, Gerolf and
Talios.
--
Nick Heudecker
Professional Wicket Training & Consulting
http://www.systemmobile.com
Eventful - Intelligent Event Management
http://www.eventfulhq.com
--
Nick Heudecker
Professional Wicket Training & Consulting
http://www.systemmobile.com
Eventful - Intelligent Event Management
http://www.eventfulhq.com
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